Understanding the different types of diabetes

The number of people afflicted by diabetes has risen significantly in recent years. What is your understanding of diabetes?

THE main sugar in the body is blood glucose, which comes from consumed food and is also made in the liver and muscles.

After a meal, blood glucose level rises. The cells in the pancreas, which is an organ in the abdomen, are stimulated to release a hormone called insulin into the bloodstream.

The insulin then attaches to the body’s cells and signals them to absorb glucose from the blood and use it for energy.

Sometimes, the body does not produce enough insulin, or the insulin does not function as it should. When this happens, glucose remains in the blood and does not reach the body’s cells. Its level rises, causing diabetes mellitus, which is a lifelong condition.

Many people have blood glucose levels above the normal range, but not high enough to be diagnosed as diabetes. This is a condition called pre-diabetes.

If the blood glucose level gets above the normal range, the risk of developing full-blown diabetes is increased.

It is important that diabetes is diagnosed and treated as early as possible because it will only worsen with time. If untreated or treated inadequately, it will cause multiple health problems.

According to the National Health and Morbidity Survey (NHMS) IV in 2011, the overall prevalence of diabetes was 15.2%. The prevalence was highest among Indians (24.9%), followed by the Malays (16.9%) and Chinese (13.8%). There were no gender differences.

The overall prevalence of known diabetes was 7.2%, and undiagnosed diabetes 8.0%. The prevalence of impaired fasting blood glucose was 4.9%.

The overall prevalence of diabetes among adults above 30 years rose from 8.3% in NHMS II in 1996 to 14.9% in NHMS III in 2006. This has significant implications for the healthcare delivery system.

Types of diabetes

There are two types of diabetes: type 1 and type 2.

Type 1 diabetes is caused by attacks of the body’s immune system on the pancreatic cells that produce insulin. Since no insulin is produced, the blood glucose is raised.

Type 1 diabetes is often called insulin-dependent diabetes. It usually develops before the age of 40 years, often when the sufferer is in the teens. Its incidence is a fraction of type 2 diabetes.

All type 1 diabetics require insulin for the rest of their lives. In addition, there has to be a healthy lifestyle to ensure that blood glucose remains within normal limits.

Type 2 diabetes is caused by insufficient production of insulin, or the failure of the body’s cells to respond to insulin. The latter is called insulin resistance. It usually develops after the age of 40 years and its incidence is about four to five times that of type 1 diabetes.

It is often associated with obesity. It is controlled by a healthy diet, regular exercise, and eventually, medicines – usually tablets. Medicines are often required at some stage because type 2 diabetes is a progressive condition.

Features of diabetes

The signs and symptoms of diabetes include feeling thirsty, hungry and/or tired; passing urine more often than usual, especially at night; weight loss without attempting to lose weight; loss of muscle bulk; feeling pins and needles in the feet; losing feeling in the feet; blurred vision; wounds that heal slowly; and itching around the genitalia or frequent fungal infections.

There may be no signs or symptoms in some people, or if there are symptoms, they are usually vague.

The only way to confirm a diagnosis of diabetes is to have a blood test.

There are two tests used to diagnose diabetes: fasting blood glucose and glucose tolerance test.

Fasting blood glucose is a reliable diagnostic test. A single blood sample is taken after an overnight fast. The normal levels are below 6.0 mmol/L. Levels above 7.0 mmol/L on two or more occasions is indicative of diabetes, and no other tests are needed.

A glucose tolerance test (GTT) is done after an overnight fast. Blood is taken for the fasting blood glucose, followed by consumption of 75g of glucose, with blood samples taken on two or four subsequent occasions within a period of up to two hours, to measure the blood glucose.

The levels rise and then fall rapidly in a non-diabetic. In a diabetic, it increases to a higher level than normal and does not fall as rapidly. The body’s response to a GTT may vary and requires interpretation by a doctor.

Blood tests are just part of the information required. The doctor will also consider the patient’s history and physical examination findings in planning the diabetic’s management.

Gestational diabetes

The placenta in a pregnant woman produces a hormone called human placental lactogen (HPL), which modifies maternal handling of carbohydrates and lipids as it makes the body less sensitive to insulin, thereby raising the mother’s blood glucose level.

HPL raises the blood glucose level so that the foetus gets enough nutrients from the extra glucose in the blood.

Another hormone, called human placental growth hormone, is also produced in pregnancy. It also ensures that the foetus gets enough nutrients by raising maternal blood glucose levels.

It is normal for maternal blood glucose levels to increase a bit during pregnancy because of the effect of the placental hormones.

However, sometimes, the increase is too high. This condition is called gestational diabetes. It usually develops between 14 and 28 weeks of pregnancy, and disappears after the baby is born.

Gestational diabetics are at increased risk of developing type 2 diabetes later in life.

It is more common in women who are above 25 years, overweight or obese, have a family history of diabetes, or who had gestational diabetes in a previous pregnancy.

Gestational diabetes could increase the risk of problems for the foetus, and also worsen type 1 diabetes. As such, it is important for a gestational diabetic to keep her blood glucose levels under control.


Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with.

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